Search over 10,000 free study notes

Breathing begins with inhalation. This starts with the contraction of the diaphragm, which flattens on contraction pulling the lungs down. The intercostal muscles contract to move the lungs up and out....

Blood is made of many components, one of them being red blood cells. These are responsible for carrying oxygen around the body. Haemoglobin is the protein molecule within red blood cells that binds to ...

Scientists have come up with many different definitions of a species over the years; reproductive isolation being key to all concepts. However the most widely accepted is the biological species concept: '...

Sources of genetic variation consist of random fertilisation and mutation. Mutation is a product of mistakes made during DNA replication. There are two main types of mutation; point gene mutation and c...

A mutation is a change in the sequence of nucleotides that make up DNA. This can be caused by a range of internal and external factors. Mutations within the coding region of genes can lead to changes i...